. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. INGESTION BY LITHODID ZOEAE 211. 25 mm Figure 4. Illustrations of the preoral chamber features and mouthparts of first-stage Plact'tnm wosnessenskii zoeae: (a) labrum; (b) paragnaths; (c) right mandible; (d) left mandible: (e) maxillule; (f) maxilla. molar regions together first, prey entering the oral region initially contact the tearing incisor processes. As the incisors are drawn across each other, the rolling motion of the mandibles results in a mouthward push of torn material from the incisors to the molar regions, to b
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. INGESTION BY LITHODID ZOEAE 211. 25 mm Figure 4. Illustrations of the preoral chamber features and mouthparts of first-stage Plact'tnm wosnessenskii zoeae: (a) labrum; (b) paragnaths; (c) right mandible; (d) left mandible: (e) maxillule; (f) maxilla. molar regions together first, prey entering the oral region initially contact the tearing incisor processes. As the incisors are drawn across each other, the rolling motion of the mandibles results in a mouthward push of torn material from the incisors to the molar regions, to be crushed by the next mandibular roll. In this way. food is broken into sequentially smaller fragments by the mandibles before entering the oral cavity. Maxillules. Each maxillule (Fig. 4c) has a three- segmented endopodite located distolaterally; a large, toothed, mesially directed basal endite; and a smaller setose coxal endite that is also mesially directed. The setae of the three endopodal segments are (progressing distally): one simple, one pappose, and three plumodenticulate or pappose setae. The basal endite is armed with three large cuspidate teeth, each tooth with two to five denticles, and often with one very small, naked tooth developing between the others. The basal endite also bears two submarginal serrate or serrulate setae. The coxal endite bears six to eight marginal setae that are plumodenticulate, serrate, simple, or a com- bination of these types and one submarginal serrate seta. The maxillules position the food prior to ingestion. An overall mesial-lateral motion is most common, with the entire maxillule moving as a lever that uses the basal at- tachment as the fulcrum, and the tips of the endites describ- ing a large arc. Anterior-posterior motions of the maxillule are also observed, with the base of the appendage again serving as the fulcrum. The endopodite of each maxillule is muscularized and seems to be capable of some independent motion both in the ant
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
